An internal combustion (IC) engine may include an exhaust gas recirculation (EGR) system for controlling the generation of undesirable pollutant gases and particulate matter in the operation of IC engines. EGR systems primarily recirculate the exhaust gas by-products into the intake air supply of the IC engine. The exhaust gas which is reintroduced to the engine cylinder reduces the concentration of oxygen therein, which in turn lowers the maximum combustion temperature within the cylinder and slows the chemical reaction of the combustion process, decreasing the formation of nitrous oxides (NOx). Furthermore, the exhaust gases typically contain unburned hydrocarbons which are burned on reintroduction into the engine cylinder, which further reduces the emission of exhaust gas by-products which would be emitted as undesirable pollutants from the IC engine.
An IC engine may also include one or more turbochargers for compressing a fluid which is supplied to one or more combustion chambers within corresponding combustion cylinders. Each turbocharger typically includes a turbine driven by exhaust gases of the engine and a compressor which is driven by the turbine. The compressor receives the fluid to be compressed and supplies the fluid to the combustion chambers. The fluid which is compressed by the compressor may be in the form of combustion air or a fuel and air mixture.
When utilizing EGR in a turbocharged diesel engine, the IC engine may use two exhaust manifolds with output flows which are joined together through a common fluid line which is coupled with the input to the turbine. The exhaust gas to be recirculated is preferably removed upstream of the exhaust gas driven turbine associated with the turbocharger. The percentage of the total exhaust flow which is diverted for introduction into the intake manifold of an internal combustion engine is known as the EGR rate of the engine, usually at an approximately 5 to 25% EGR rate.
What is needed in the art is an EGR system having a high EGR rate of approximately 50% of the total exhaust flow from the exhaust manifolds.